Method and apparatus for improving continuous packet connectivity in a wireless communications system

ABSTRACT

A method of improving CPC for a UE in a wireless communications system includes receiving a reconfiguration message, determining the content of a second information element, abbreviated to IE, included in a first IE when the first IE is included in the reconfiguration message, wherein the first IE is used for indicating timing information of a discontinuous transmission and discontinuous reception, abbreviated to DTX-DRX, operation and the second IE is used for selecting a timing of the DTX-DRX operation, and using the content of the first IE without storing the content of the first IE when the content of the second IE is a new timing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/953,472, filed on Aug. 2, 2007 and entitled “Method and Apparatus forImproving the DTX-DRX Operation in CPC (Continuous PacketConnectivity)”, the contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and related apparatus forimproving Continuous Packet Connectivity in a wireless communicationssystem, and more particularly, to a method and related apparatus forimproving a start procedure of DTX-DRX operation, for improvingContinuous Packet Connectivity.

2. Description of the Prior Art

The third generation (3G) mobile telecommunications system, theUniversal Mobile Telecommunications System (UMTS), has adopted aWideband Code Division Multiple Access (WCDMA) wireless air interfaceaccess method for a cellular network. WCDMA provides high frequencyspectrum utilization, universal coverage, and high quality, high-speedmultimedia data transmission. The WCDMA method also meets all kinds ofQoS (Quality of Service) requirements simultaneously, providing diverse,flexible, two-way transmission services and better communication qualityto reduce transmission interruption rates. Through the 3G mobiletelecommunications system, a user can utilize a wireless communicationsdevice, such as a mobile phone, to realize real-time videocommunications, conference calls, real-time games, online musicbroadcasts, and email sending/receiving. However, these functions relyon fast, instantaneous transmission. Thus, targeting the thirdgeneration mobile telecommunication technology, the prior art providesHigh Speed Package Access (HSPA) technology, which includes High SpeedDownlink Package Access (HSDPA) and High Speed Uplink Package Access(HSUPA), to increase bandwidth utility rate and package data processingefficiency to improve uplink/downlink transmission rate.

According to the related protocol specifications, one of protocol stacksof the UMTS, access stratum (AS), can be segmented into sub-layers fordifferent functions. The operations of the sub-layers in the AS are wellknown in the art, and detailed description is not given here. The RadioResource Control (RRC) layer, a Layer 3 protocol, is the core ofcommunications protocols related to AS and is located in radio networkcontrollers (RNC) of the UMTS Terrestrial Radio Access Network (UTRAN)and a user equipment (UE). The RRC layer uses RRC messages to performRRC procedures. RRC messages are formed from many information elements(IEs) used for embedding necessary information for setting, changing, orreleasing protocol entities of Layer 2 and Layer 1, therebyestablishing, adjusting, or canceling information exchange channels toperform data packet transportation.

For improving HSDPA and HSUPA, the 3rd Generation Partnership Project(3GPP) provides a Continuous Packet Connectivity (CPC) protocolspecification, which includes features that, for UEs in CELL_DCH state,aim to significantly increase the number of packet data users for acell, reduce the uplink noise rise and improve the achievable downloadcapacity for VoIP.

According to the CPC protocol specification, a discontinuoustransmission and discontinuous reception (DTX-DRX) operation is used toreduce power consumption when transmission between a UE and the UTRAN isdecreasing. The DTX-DRX operation includes discontinuous uplinktransmission (uplink DTX), discontinuous uplink reception (uplink DRX)and discontinuous downlink reception (downlink DRX). Uplink DTX is amechanism where control signals are transmitted on the uplink controlchannels according to defined discontinuous patterns during the inactivestate of corresponding uplink data channels, such as Enhanced DedicatedTransport Channel (E-DCH) or High Speed Physical Control Channel(HS-DPCCH), in order to maintain signal synchronization and powercontrol loop with less control signaling. Uplink DRX is utilized forcontrolling the UE to transmit E-DCH in specific time interval and hasto be configured with uplink DTX. Downlink DRX is configured by a RadioNetwork Controller (RNC) and allows the UE to restrict the downlinkreception times in order to reduce power consumption. When the downlinkDRX is enabled, the UE is not required to receive physical downlinkchannels except for several specific situations. Please note that theDTX-DRX operation is enabled only when the UE is in CELL_DCH state.

Associated configurations of the DTX-DRX operation are described asfollows. If the UE receives RRC CONNECTION SETUP, ACTIVE SET UPDATE,CELL UPDATE CONFIRM, or any other reconfiguration message, the UE shalldetermine the value for a DTX_DRX_STATUS variable that indicates astatus of the DTX-DRX operation. The DTX_DRX_STATUS variable shall beset to TRUE for starting the DTX-DRX operation only when all thefollowing conditions are met:

1. the UE is in CELL_DCH state;

2. both variables HS_DSCH RECEPTION and E_DCH_TRANSMISSION are set toTRUE;

3. no DCH transport channel is configured;

4. a variable DTX_DRX_PARAMS is set; and

5. the UE received an IE “DTX-DRX timing information”.

If any one of the above conditions is not met and the variableDTX_DRX_STATUS is set to TRUE, the UE shall:

1. set the variable DTX_DRX_STATUS to FALSE;

2. clear the variable DTX_DRX_PARAMS; and

3. stop the DTX-DRX operation related activities.

In summary, the UE controls start or stop of the DTX-DRX operation bysetting the variable DTX_DRX_STATUS to TRUE or FALSE. On the other hand,the UE stores the content of the received IE “DTX-DRX timinginformation” in the variable DTX_DRX_PARAMS. The variable DTX_DRX_PARAMSincludes the IE “DTX-DRX timing information” and an IE “DTX-DRXinformation”. The IE “DTX-DRX timing information” is used for indicatingtiming information of the DTX-DRX operation and comprises other IEs,such as an IE “CHOICE timing”, an IE “DTX information”, an IE “DRXinformation”, and so on. The UTRAN has to transmit the IE “CHOICEtiming” using for selecting a timing of the DTX-DRX operation to the UEto reconfigure the timing of the DTX-DRX operation. The content of theIE “CHOICE timing” comprises “new timing” or “continue”.

Known as associated 3GPP protocols, if the UE confirms that the IE“DTX-DRX timing information” is included in a received reconfigurationmessage and the IE “CHOICE timing” is set to “new timing”, the UE storesthe content of the IE “DTX-DRX timing information” in the variableDTX_DRX_PARAMS. At the same time, if the UE confirms that the IE“DTX-DRX information” is included in the received reconfigurationmessage, the UE also stores the content of the IE “DTX-DRX information”in the variable DTX_DRX_PARAMS.

In fact, if the UE confirms that the IE “CHOICE timing” is set to “newtiming”, the UE can use the content of the IE “DTX-DRX timinginformation” and does not store it in the variable DTX_DRX_PARAMS. TheUE only stores the IE “DTX-DRX information” in the variableDTX_DRX_PARAMS.

From the above, the UE starts the DTX-DRX operation only when all theabove 5 conditions are met. In other words, the UE stops the DTX-DRXoperation only when any one of the above 5 conditions is repealed. Forexample, the UE has to leave CELL_DCH state, or sets the variablesHS_DSCH RECEPTION and E_DCH_TRANSMISSION to FALSE in order to stop theDTX-DRX operation after the DTX-DRX operation is enabled. In otherwords, the UE has to disable HSDPA and HSUPA for stopping the DTX-DRXoperation. If the UE wants to keep transmission, the UE has to enterCELL_DCH state again. In addition, the variable DTX_DRX_PARAMS is setand the IE “DTX-DRX timing information” is received after the DTX-DRXoperation is enabled. Therefore, it is impossible to stop the DTX-DRXoperation by repealing the last two of the above 5 conditions.

In conclusion, it is difficult to stop the DTX-DRX operation byrepealing any one of the above 5 conditions when the DTX-DRX operationis enabled. Therefore, transmission efficiency of CPC is decreased.

SUMMARY OF THE INVENTION

The present invention provides a method and related apparatus forimproving CPC for a UE in a wireless communications system.

The present invention discloses a method of improving CPC for a UE in awireless communications system. The method includes receiving areconfiguration message, determining the content of a second IE includedin a first IE when the first IE is included in the reconfigurationmessage, wherein the first IE is used for indicating timing informationof a DTX-DRX operation and the second IE is used for selecting a timingof the DTX-DRX operation, and using the content of the first IE withoutstoring the content of the first IE when the content of the second IE isa new timing.

The present invention further discloses a communications device used ina wireless communications system for improving CPC. The communicationsdevice includes a control circuit for realizing functions of thecommunications device, a central processing unit installed in thecontrol circuit for executing a program code to operate the controlcircuit, and a memory coupled to the central processing unit for storingthe program code. The program code includes receiving a reconfigurationmessage, determining the content of a second IE included in a first IEwhen the first IE is included in the reconfiguration message, whereinthe first IE is used for indicating timing information of a DTX-DRXoperation and the second IE is used for selecting a timing of theDTX-DRX operation, and using the content of the first IE without storingthe content of the first IE when the content of the second IE is a newtiming.

The present invention further discloses a method of improving CPC for aUE in a wireless communications system. The method includes receiving areconfiguration message, and starting a DTX-DRX operation when the UEmeets a plurality of conditions and confirms that a specific IE isincluded in the reconfiguration message, wherein the specific IE is usedfor storing timing information of the DTX-DRX operation.

The present invention further discloses a communications device used ina wireless communications system for improving CPC. The communicationsdevice includes a control circuit for realizing functions of thecommunications device, a central processing unit installed in thecontrol circuit for executing a program code to operate the controlcircuit, and a memory coupled to the central processing unit for storingthe program code. The program code includes receiving a reconfigurationmessage, and starting a DTX-DRX operation when the communications devicemeets a plurality of conditions and confirms that a specific IE isincluded in the reconfiguration message, wherein the specific IE is usedfor storing timing information of the DTX-DRX operation.

The present invention further discloses a method of improving CPC for anetwork terminal in a wireless communications system. The methodincludes generating a reconfiguration message, adding a second IE to thereconfiguration message when the network terminal confirms that a firstIE is included in the reconfiguration message, wherein the first IE isused for indicating information of a DTX-DRX operation and the second IEis used for indicating timing information of the DTX-DRX operation, andtransmitting the reconfiguration message to a user equipment in thewireless communications system.

The present invention further discloses a communications device used ina wireless communications system for improving CPC. The communicationsdevice includes a control circuit for realizing functions of thecommunications device, a central processing unit installed in thecontrol circuit for executing a program code to operate the controlcircuit, and a memory coupled to the central processing unit for storingthe program code. The program code includes generating a reconfigurationmessage, adding a second IE to the reconfiguration message when thecommunications device confirms that a first IE is included in thereconfiguration message, wherein the first IE is used for indicatinginformation of a DTX-DRX operation and the second IE is used forindicating timing information of the DTX-DRX operation, and transmittingthe reconfiguration message to a user equipment in the wirelesscommunications system.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a communications device.

FIG. 2 is a diagram of the program code shown in FIG. 1.

FIG. 3 to FIG. 5 are flowcharts of processes according to embodiments ofthe present invention.

FIG. 6 is a schematic diagram of a communications system.

DETAILED DESCRIPTION

Please refer to FIG. 6, which is a schematic diagram of a wirelesscommunications system 600. The wireless communications system 600 ispreferably a High Speed Package Access (HSPA) system, and is brieflycomposed of a network and a plurality of user equipments (UEs). In FIG.6, the network and the UEs are simply utilized for illustrating thestructure of the wireless communications system 600. Practically, thenetwork may comprise a plurality of base stations (or Node B), radionetwork controllers and so on according to actual demands, and the UEscan be devices such as mobile phones, computer systems, etc.

Please refer to FIG. 1, which is a functional block diagram of acommunications device 100. The communications device 100 can be used forimplementing the network or the UE shown in FIG. 4. For the sake ofbrevity, FIG. 1 only shows an input device 102, an output device 104, acontrol circuit 106, a central processing unit (CPU) 108, a memory 110,a program code 112, and a transceiver 114 of the communications device100. In the communications device 100, the control circuit 106 executesthe program code 112 in the memory 110 through the CPU 108, therebycontrolling an operation of the communications device 100. Thecommunications device 100 can receive signals input by a user throughthe input device 102, such as a keyboard, and can output images andsounds through the output device 104, such as a monitor or speakers. Thetransceiver 114 is used to receive and transmit wireless signals,deliver received signals to the control circuit 106, and output signalsgenerated by the control circuit 106 wirelessly. From a perspective of acommunications protocol framework, the transceiver 114 can be seen as aportion of Layer 1, and the control circuit 106 can be utilized torealize functions of Layer 2 and Layer 3. Preferably, the communicationsdevice 100 is utilized in the HSPA system, supporting Continuous PacketConnectivity (CPC).

Please continue to refer to FIG. 2. FIG. 2 is a diagram of the programcode 112 shown in FIG. 1. The program code 112 includes an applicationlayer 200, a Layer 3 202, and a Layer 2 206, and is coupled to a Layer 1208. The Layer 3 202 is for performing radio resource control (RRC). TheLayer 2 206 is for performing link control, and the Layer 1 208 is aphysical layer.

According to the prior art, after a discontinuous transmission anddiscontinuous reception (DTX-DRX) operation is enabled, if the UEconfirms that an information element (IE) “DTX-DRX timing information”is included in a received reconfiguration message and the content of anIE “CHOICE timing” included in the IE “DTX-DRX timing information” is“new timing”, the UE does not only use the content of the IE “DTX-DRXtiming information” but stores the content of the IE “DTX-DRX timinginformation” in a variable DTX_DRX_PARAMS. The embodiment of the presentinvention provides a CPC program code 220 for the program code 112 inthe Layer 3 202, for using the IE “DTX-DRX timing information” withoutstoring the IE “DTX-DRX timing information”, so as to improve theDTX-DRX operation, and moreover, to improve efficiency of CPC. Pleaserefer to FIG. 3, which is a flowchart of a process 30 according to anembodiment of the present invention. The process 30 is utilized forimproving CPC for a UE in the wireless communications system 600, andcan be compiled into the CPC program code 220. The process 30 includesthe following steps:

Step 300: Start.

Step 302: Receive a reconfiguration message.

Step 304: Determine the content of a second IE included in a first IEwhen the first IE is included in the reconfiguration message, whereinthe first IE is used for indicating timing information of a DTX-DRXoperation and the second IE is used for selecting timing of the DTX-DRXoperation.

Step 306: Use the content of the first IE without storing the content ofthe first IE when the content of the second IE is a new timing.

Step 308: End.

In the process 30, the first IE is the IE “DTX-DRX timing information”,and the second IE is the IE “CHOICE timing”. The content of the IE“CHOICE timing” comprises “new timing” or “continue”. According to theprocess 30, when the UE receives the reconfiguration message andconfirms that the IE “DTX-DRX timing information” is included in thereconfiguration message, the UE then determines the content of the IE“CHOICE timing” included in the IE “DTX-DRX timing information”. Whenthe content of the IE “CHOICE timing” is “new timing”, the UE uses thecontent of the IE “DTX-DRX timing information” and does not store thecontent of the IE “DTX-DRX timing information”. That is, the UE does notstore the content of the IE “DTX-DRX timing information” in the variableDTX_DRX_PARAMS.

In the prior art, when the content of the IE “CHOICE timing” is “newtiming”, the UE shall store the content of the IE “DTX-DRX timinginformation” in the variable DTX_DRX_PARAMS when not using it. Incomparison, the UE uses the content of the IE “DTX-DRX timinginformation” and does not store the content of the IE “DTX-DRX timinginformation” according to the process 30. Therefore, the unnecessarystep of storing can be canceled for improving efficiency of CPC.

According to the prior art, after the DTX-DRX operation is enabled, theUE can stop the DTX-DRX operation only when any one of the followingconditions is repealed:

1. the UE is in CELL_DCH state;

2. both variables HS_DSCH RECEPTION and E_DCH_TRANSMISSION are set toTRUE;

3. no DCH transport channel is configured;

4. a variable DTX_DRX_PARAMS is set; and

5. the UE received an IE “DTX-DRX timing information”.

In the aspect of the UE, transmission efficiency will be reduced if theUE stops the DTX-DRX operation by repealing the condition 1, 2 or 3. Onthe other hand, after the DTX-DRX operation is enabled, it is impossibleto stop the DTX-DRX operation by repealing the condition 4. Please notethat the condition 5 means that the UE can start the DTX-DRX operationonly when the IE “DTX-DRX timing information” is included in thereceived reconfiguration message. In other words, when the UE confirmsthat the IE “DTX-DRX timing information” is not included in the receivedreconfiguration message, the UE can stop the DTX-DRX operation.

Please refer to FIG. 4, which is a flowchart of a process 40 accordingto an embodiment of the present invention. The process 40 is utilizedfor improving CPC for a UE in the wireless communications system 600,and can be compiled into the CPC program code 220. The process 40includes the following steps:

Step 400: Start.

Step 402: Receive a reconfiguration message.

Step 404: Start a DTX-DRX operation when the UE meets a plurality ofconditions and confirms that a specific IE is included in thereconfiguration message, wherein the specific IE is used for storingtiming information of the DTX-DRX operation.

Step 406: End.

In the process 40, the plurality of conditions is the conditions 1-5 asabove, and the specific IE is the IE “DTX-DRX timing information”.According to the process 40, only when the UE meets the conditions 1-4and the UE confirms that the IE “DTX-DRX timing information” is includedin the reconfiguration message, does the UE set a variableDTX_DRX_STATUS to TRUE to start the DTX-DRX operation.

In other words, if the IE “DTX-DRX timing information” is not includedin the received reconfiguration message, one of the conditions forstarting the DTX-DRX operation is repealed so that the DTX-DRX operationshould be stopped. For example, if the IE wants to stop the DTX-DRXoperation after the DTX-DRX operation is enabled, the receivedreconfiguration message will not include the IE “DTX-DRX timinginformation”, and therefore the UE can stop the DTX-DRX operation. In aword, the embodiment of the present invention changes the conditions forstarting the DTX-DRX operation, so that the UE can stop the DTX-DRXoperation easier instead of leaving CELL_DCH state or leaving the HSPA.Therefore, the embodiment of the present invention prevents transmissionefficiency from being reduced.

In addition, when an IE “DTX-DRX information” is included in thereceived reconfiguration message, the IE “DTX-DRX timing information”has to be included in the same message and the content of the IE “CHOICEtiming” included in the IE “DTX-DRX timing information” should be “newtiming”, otherwise unknown behavior may occur. In this situation, thepresent invention provides a process 50 in a network terminal, fortransmitting a correct reconfiguration message to the UE for avoidingunknown behavior. Please refer to FIG. 5, which is a flowchart of theprocess 50 according to an embodiment of the present invention. Theprocess 50 is utilized for improving CPC for a network terminal in thewireless communications system 600, and can be compiled into the CPCprogram code 220. The process 50 includes the following steps:

Step 500: Start.

Step 502: Generate a reconfiguration message.

Step 504: Add a second IE to the reconfiguration message when thenetwork terminal confirms that a first IE is included in thereconfiguration message, wherein the first IE is used for indicatinginformation of a DTX-DRX operation and the second IE is used forindicating timing information of the DTX-DRX operation.

Step 506: Transmit the reconfiguration message to a UE in the wirelesscommunications system.

Step 508: End.

In the process 50, the first IE is the IE “DTX-DRX information”, and thesecond IE is the IE “DTX-DRX timing information”. According the process50, when the network terminal confirms that the IE “DTX-DRX information”is included in the reconfiguration message, the network terminal addsthe IE “DTX-DRX timing information” to the reconfiguration message andthen transmits the reconfiguration message to the UE. As a result, thereconfiguration message received by the UE will include the IE “DTX-DRXinformation” and the IE “DTX-DRX timing information”, so that unknownbehavior of the UE can be avoided.

Please note that when the IE “DTX-DRX information” and the IE “DTX-DRXtiming information” are included in the same reconfiguration message,the content of the IE “CHOICE timing” should be “new timing”. Inaddition, if the IE “DTX-DRX information” is not included but the IE“DTX-DRX timing information” is included in the reconfiguration message,the network terminal still transmits the reconfiguration message to theUE, so that the UE can keep using the DTX-DRX operation. Note that thecontent of the IE “DTX-DRX timing information” is “continue” in thissituation. Compared with the prior art, the embodiment of the presentinvention avoids unknown behavior.

In conclusion, according to the embodiment of the present invention, theUE uses the content of the IE “DTX-DRX timing information” and does notstore the content of the IE “DTX-DRX timing information”, and thereforethe unnecessary step of storing can be canceled for improving efficiencyof CPC. Moreover, the embodiment of the present invention changes theconditions for starting the DTX-DRX operation, so that the UE can stopthe DTX-DRX operation easier. Additionally, the embodiment of thepresent invention changes the content of reconfiguration message so thatthe IE “DTX-DRX timing information” and the IE “DTX-DRX timinginformation” are both included in the same reconfiguration message.Therefore, unknown behavior of the UE can be avoided.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method of improving Continuous Packet Connectivity (CPC) for a user equipment, called UE hereafter, in a wireless communications system, the method comprising: receiving a reconfiguration message; determining the content of a second information element (IE) included in a first IE when the first IE is included in the reconfiguration message, wherein the first IE is used for indicating timing information of a discontinuous transmission and discontinuous reception (DTX-DRX) operation and the second IE is used for selecting a timing of the DTX-DRX operation; and using the content of the first IE without storing the content of the first IE when the second IF indicates a new timing.
 2. The method of claim 1, wherein the new timing will be transmitted to the UE when a network terminal in the wireless communications system wants to reconfigure the timing of the DTX-DRX operation.
 3. The method of claim 1, wherein the first IF is a DTX-DRX timing information IE.
 4. The method of claim 1, wherein the second IE is a choice timing IE and the content of the choice timing IE comprises “new timing” or “continue”.
 5. The method of claim 1, wherein the content of the first IE is not stored in a DTX-DRX operation parameter variable that is used for storing associated parameters of the DTX-DRX operation.
 6. A communications device used in a wireless communications system for improving Continuous Packet Connectivity (CPC), the communications device comprising: a control circuit for realizing functions of the communications device; a central processing unit installed in the control circuit for executing a program code to operate the control circuit; and a memory coupled to the central processing unit for storing the program code; wherein the program code comprises: receiving a reconfiguration message; determining the content of a second information element (IE) included in a first IE when the first IE is included in the reconfiguration message, wherein the first IE is used for indicating timing information of a discontinuous transmission and discontinuous reception (DTX-DRX) operation and the second IE is used for selecting a timing of the DTX-DRX operation; and using the content of the first IE without storing the content of the first IE when the second IE indicates a new timing.
 7. The communications device of claim 6, wherein the new timing will be transmitted to the communications device when a network terminal in the wireless communications system wants to reconfigure the timing of the DTX-DRX operation.
 8. The communications device of claim 6, wherein the first IE is a DTX-DRX timing information IE.
 9. The communications device of claim 6, wherein the second IE is a choice timing IE and the content of the choice timing IE comprises “new timing” or “continue”.
 10. The communications device of claim 6, wherein the content of the first IE is not stored in a DTX-DRX operation parameter variable that is used for storing associated parameters of the DTX-DRX operation.
 11. A method of improving Continuous Packet Connectivity (CPC) for a network terminal in a wireless communications system, the method comprising: generating a reconfiguration message; adding a second information element (IE) to the reconfiguration message when the network terminal confirms that a first IE is included in the reconfiguration message, wherein the first IE is used for indicating information of a discontinuous transmission and discontinuous reception (DTX-DRX) operation and the second IE is used for indicating timing information of the DTX-DRX operation; transmitting the reconfiguration message to a user equipment in the wireless communications system; and stopping the DTX-DRX operation when the second IE is not included in the reconfiguration message.
 12. The method of claim 11, wherein the first IE is a DTX-DRX information IE.
 13. The method of claim 11, wherein the second IE is a DTX-DRX timing information IE.
 14. The method of claim 11, wherein the content of the second IE is a new timing.
 15. The method of claim 11 further comprising: transmitting the reconfiguration message to the user equipment when the network terminal confirms that the first IE is not included but the second IE is included in the reconfiguration message.
 16. A communications device used in a wireless communications system for improving Continuous Packet Connectivity (CPC), the communications device comprising: a control circuit for realizing functions of the communications device; a central processing unit installed in the control circuit for executing a program code to operate the control circuit; and a memory coupled to the central processing unit for storing the program code; wherein the program code comprises: generating a reconfiguration message; adding a second information element (IE) to the reconfiguration message when the communications device confirms that a first IE is included in the reconfiguration message, wherein the first IE is used for indicating information of a discontinuous transmission and discontinuous reception (DTX-DRX) operation and the second IE is used for indicating timing information of the DTX-DRX operation; transmitting the reconfiguration message to a user equipment in the wireless communications system; and stopping the DTX-DRX operation when the second IE is not included in the reconfiguration message.
 17. The communications device of claim 16, wherein the first IE is a DTX-DRX information IE.
 18. The communications device of claim 16, wherein the second IE is a DTX-DRX timing information IE.
 19. The communications device of claim 16, wherein the content of the second IE is a new timing.
 20. The communications device of claim 16, wherein the program code further comprises: transmitting the reconfiguration message to the user equipment when the communications device confirms that the first IE is not included but the second IE is included in the reconfiguration message. 